Agent for cleaning and imparting rust-inhibitive properties to steel



I Patented Dec-618,128. I i *UNITED'STATES PATENT OFFICE.

nuns n.'xr.i1venn,'or Damon, moment;

No Drawing.

My invention relates to an improved method of cleaning and preparingsteel for painting. The ob ectis to provide an improved method and agentthrough the use of which steel may be cleaned and rust resistingproperties imparted hereto.

This invention is particularly valuable in 4 connection with thepreparation of the sheet erties thereto.

steel employed in the manufacture of automobile bodies. The grease,dirt, oil, rust, etc., must be cleaned from this sheet steel and thesurface prepared to receive the priming coat of paint. To meet thiscommercial demand, itis essential that the method, and agent em: ployedtherein, be inexpensive, and that the process be a rapid one. Byfollowing my improved process the steel is thoroughly cleaned so as toreceive and retain. the priming coat of paint and the surface of. themetal is rendered substantially immune to the subsequent action of rust.

' I provide a suitable cleaning solution which is applied as a wash or abath to the metal to be treated to remove the grease, oil, dirt,

: rust, etc. For this purpose I prefer to employ a solution composedofan effective rust attacking and removing acid, such as sulfuric acid,and a solvent for. the oil, grease, etc., suchas alcohol or acetone.Denatured alcohol containing a small percentage of acetone makes a verysatisfactory solvent. j

I have found that by using a cleaning solution such as above containingas an added ingredient, a suitable 'hydroxycarboxylio acid, that rustinhibitive properties willbe imparted to the surface of the metal. Thehydroxycarboxylic acid in the solution acts upon the metal and preventsthe formation of iron hydroxide, which is the first stage of rust, andwhich otherwise would occur as a. result of the presence of the sulfuricacid'and the water. I prefer to employ in this connection a hy-.droxytricarboxylic acid, of which the most common one is citric acid.However, hydroxydicarboxylic acid, such as tartaric acid is effectivefor the purpose.

Generally stated, this invention consists in applying a fluid admixtureof a hydroxycarboxylic acid, a rust attacking and removing acid and asolvent for oil and grease to the steel to be treated, which solutionremoves all oil, grease, dirt, rust, etc., from the surface of thematerial and gives it a bright, clean finish, prevents the formation ofiron hydroxide thereon, and imparts rust resisting prop- Applicationfiled June 27,

. ingredients in substantially Aomir ron CLEARING- AND mrAm-menUsr-INHIBIrIvE' rnornn'rms r0 srmam.

1924. Serialflo. 722,720.

The cleaning solution may be applied to the metal by painting orspraying the metal therewith. A period from two to three minutes shouldbe allowed for the solution to act. In cases where there is deep-seatedrust on the steel the cleaning'solution and the resultant products ofthe cleaning action are washed from the steel byrinsing with hot or coldwater. If cold Water is used, it should be flowed on freely and thewaterremaining on the steel blown ofi' with air. If hot water is used anywater that has not evaporated should be blown off with air. .The watershould be completely removed from the surface of the metal and'it may benecessary to torch ofi' around mouldings or pockets with a gas flame todrive out the remaining water. I The steel should then be saturated withturpentine or alcohol andplaced in a pre-heat oven to dry. The steel isnow ready to receive the priming coatrof paint.

The strength of the solution and the proportion of the respectiveingredients may be varied to meet the exigencies of the. material vto becleaned. I have found, however, that a solution comprising sulfuricacid, citric acid and denatured alcohol having a small per.- centage ofacetone is particularly effective, and, a very satisfactory strength isto provide these ingredients in the proportion, byvolume, of-thirty-fiveparts of an aqueous solution 'of citric acid (strength of solutiontwenty per cent), five parts of concentrated sulfuric acid, fifty partsof denaturedalcohol and ten parts of acetone.

What I claim is:

1. A solutionto be used in the cleaning of steel and the imparting ofrust inhibitive properties thereto containin he approximate volume offive parts of alcohol,four parts of citric acid and one part of sulfuricacid.

2. A solution to be used in the cleaning of steel and the imparting ofrust inhibitive properties theretocontaining the following wiped with acloth 7 the following imparting rust resisting properties to st'e'elcontaining a solvent for grease and oil, a rust removing acid and ahydroxycarboxylic? acid. L

A solution to be used for cleaning and imparting rust resistingproperties to steel 6. A. solution to be used for cleaning andcontaining denatured alcohol, an aqueous soimparting rustresistingproperties to steel lution of citric acid, sulfuric acid and asmall containing a hydroxytricarboxylic acid. 1o

6 5. A solution to be used for cleaning and tion.

imparting rust resistin properties to steel I containing a hydroxycaroxylic acid. JAMES D. KLINGER.

percentage of acetone. In testimony whereof, I sign this specifica-

